The present invention is directed generally to a system and method for controlling brake actuation energy in electronically controlled brake systems (“EBSs”) of tractor and trailer vehicle combinations.
In tractor and trailer vehicle combinations (“vehicle trains”), it is known to superpose coupling force control on the electronic control of brake actuation energy in order to control the set pressure of the trailer vehicle train part. The objective of such coupling force control is a coupling force of zero, so that no force at all or only a force of small magnitude (tolerance range) is transmitted via the trailer coupling from the trailer vehicle train part to the tractor vehicle train part, or vice-versa, during braking.
If the wheel brakes of the tractor and trailer vehicle train parts develop different wheel brake temperatures, e.g., due to different distribution of load between the tractor vehicle train part and the trailer vehicle train part, the braking power of the wheel brakes having higher temperatures will be less than the braking power of the wheel brakes having lower temperatures at the same brake actuation energy, resulting in a non-zero coupling force. By virtue of the zero coupling force control objective of the coupling force control system, a shift of brake actuation energy to the vehicle train part having the hotter wheel brakes is effected. This can present a possible overheating situation and associated undesired reduction in braking power if the temperatures of the wheel brakes reach a defined limit value.
Accordingly, it is desired to provide an improved system and method for controlling brake actuation energy in a vehicle train equipped with a coupling force control system that compensate for the zero coupling force control objective of the coupling force control system when appropriate to prevent overheating of wheel brakes during braking and undesired reduction in braking power.